BIOLOGY OF THE SOFT BROWN SCALE , COCCU S HE SP ERIDU.-i LINN ., AND CONTROL OF SOF'r d C \ L.E S ON HOLLY by WARREN CLIFFORD ADLERZ
A THESIS submitted to
OREGON STATE COLLEGE
in partial fulfillment of the requirements for t h e degree of
!A v T ER OF S CIENCE June 1955 APFROVEDI Redacted for Privacy
Aggoolate Prtofereor of, Departnent of &rtorc1o6y fn 0hargo of ll3Jor .:- Redacted for Privacy
Chelrma of Dopentuost of Strrtorologt
Redacted for Privacy
Chnlrren of 8ohool Oneduets Conmlttcr Redacted for Privacy
Drcn of Orrduatc $ohool
Drtc thasla le prorori1,oa F4 ^r, {1,, typoC by R:lta P. ldlcra ACKNO\iLEDGilENT
The writer wiehe to ex~reBs sincere ap rec1ation to Dr . Knud G• . Swenson, Associate Professor, Oregon State College, under whose patient guidance this work was undertaken and completed. The writer would like to express hi appreciation to Dr . Paul o. Ritcher, Head of the Department of
Entomology , for his guidance ~nd eneoura ~ ement .
The writer is also indebted 't-O Dr . Charles H. Martin, ssooiate Professor. for helpful criticism of this thesis a nd Mr. E. A. Dickason , Asaistant Entomo og1st, Oregon Agricultural Experiment 5tation, for his gu1d nee in photography wnich resulted in illustl'ation of t,he thesis . To the staff and friends of the writer at Oregon vtate College , the writer expresses his gratitude. The writer is sincerely grateful to his wife , Rita P . Adlerz , for constant faith and encouragement. TABLE OF CONTENTS
INTRODUCTION ...... 1 E:CONOMI C I~PORTANCE • • • • • • • • • • • • • • • • • • • • • • • • • • • 2 DISTRIBUTION , HOSTS , 1\ND INJURY • • • • • • • • • • • • • • • 5 T. "ONOMIC GT TU S '\ D DESCRI'PTION • • • • • • • • • • • • • • 6 T~ONOMIC POSITION . ~ ...... 6 SYNONYMY ...... 8 Dl!:vCRIPTION ...... 11
DE1;CRI ?TI ON OF bTAGES • • • • • • • • • • • • • • • • • • • • • • • • • 12 FI RST !NOT~ .•• ...... 12 lJECOND INJTAR ~ ...... 14 DULT • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 16
!..IFE HISTORY AND HABITS • • • • • • • • • • • • • • • • • • • • • • • 18 bEASONAL HISTORY • • • • • • • • • • • • • • • • • • • • • • • •• • 18 BI RTH OF CRAWLERS • • • • • • • • • • • • • • • • • • • • • • • • 21 FECUNDI TY • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 22 MOVEMENT OF CRAt'lLERS ~ND ADULTS • • • • • • • • • • 24 DI SPERSAL • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 24 }110LTI NG .~ ...... 25 TEMPERATURE RELATI ONS • • • • • • • • • • • • • • • • • • • • 25 DI SCUSSION ...... 26 OO~TROL ...... 27 GOFT BRO\'lN SCALE ...... - ~ ...... 27 N TURJ\L CONTROL ...... 27 CH~MIC ~L CONTROL • • • • • • • • • • • • • • • • • • • • 29
Lt!:CANIU~~ • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 32 PULVIlARIA ...... 34 ~JNG!C I D€ COMPATIBILI TY ...... 37 DI ..>CUJSION ...... 38 SUMMARY ...... 40 BI BLI OG PHY • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •• • • 43 APPENDI X ...... 46 LIST OF TABLES
Table
1 . ~1 ea surementn o crawlers in millimeters . 11t ·2 . Measurements of the firat 1natar settled s tage , in millimeter - • •••••••• 15 3 . Measurements of the second instar in mil 1m t or • ••••••••····~··••••••••• 17 4. "'1easur0mento of the adult i mmedia.·tely after the second ecdysis , in millimeters . ••••••••••••••••••••••••••• 18 5. Measurements of the fully matured adult, in millimeters . •• • •••••••••• · ••• 19 6 . Comparison of temperature data for experiment site and Corvallis for the period July 1 to November 30 . •••••• 25 1. Comparison of malathion and chlorth1on for control of Coccus hesper1dum on holly , Tigard, Oregon , 1954. • •• • •• •• •• • 33 8 . Comparison of three insecticides for control of Lecan1um nym hs on holly , Tigard, Oregon , 1954. • • • • • • • • • • • • • • • • • • 35 9. Comparison of malathion and chlorthion for control of Pulv1nar1a nymphs on camellia, Corvallis , Oregon, 1954. ••••• 37 LIST OF FIGURES
F1s ure 1. Soft brown scale . A fully matured adult and two crawlers . t1v1ng specimens on holly. Eleven times natural size. • • •. • • • • • • • • • • • • • • • • • • • • .• • • 46 2 . Soft brown scal e . nettled first and second 1natar nymphs on holly ...... 47 3 . Lecanium sp. Bodies of dead adults found covering eggs in the spring, on holly.. • • .. • • • • • • • • .• • • • • • • • • • • • .. • • • • • • 48 4 . Camellia scale . Immature stages. Early summer condition after eggs have hatched. Note number of individuals . •••••••• •••• 49 5. Camellia soale . Frothy egg masse s in June . Newly hatched nymphs oan also be seen her e . • • • • • • • • • • • • • • • • • • . • • • • .. • • • • • 50 BIOLOGY OF THE SOFT BR0 1ffl SCALE, COCCU t> HESPERI DUM LINN . ,1 AND CONTROL OF SOFT 13 CALE:J ON HOLLY
INTRODUCTION
The original descri t1on of the soft brown scale, Coccus hesner1dum L. • t.zas puol_is. hed in 1758 by Linnaeus 1n the tenth ed1t1on ·Of " Bystema Naturae 11 (12, p . 445) . This scale ts distributed. throughout the world and exhibits ·an amazing ada tab111ty in host select1on In Oregon the soft bro~m s ca le is a. common ·pest on ornamental plants , one of which i s holly .. Holly 1a an import nt plant in the s t a te of Oregon . · It is cultured extens ively 1n orchards where marketing of cut holly i s the objective and· it is utilized ~reely in landscaping. The scales ca.n be present in sufficient numbers to deface the leaves with their Ol'lrl bodies,. In addition the sooty mold which grows on their exudates can render the leaves orthlees f or \decoration or dis play . Both the home owner and the commercial grower are f a ced with these problems . \"fork on the other two scales included , 'tecaniurn sp. 1 . Sca les studied were identified by Dr. Harold Morrison, u ~s . o . A ., Agricultural Research uerv1oe, Beltsville . Md . 2 and :Pulv1n~r1a flocc1fera (West . ), comes a .s a natural outgrowth of the original problem. They are also in the group known as soft scales and are detrimental in a way similar to the soft brown scale. The three scales may occur on the same hosts and are difficult to dis tinSuish from one another except as adults or when reproducing. In the re roductive condition, eggs are found beneath Lecan1um scales . Eggs occur in a frothy mass behind Pulvinaria scales and living young are found beneath soft brown scales . As adults,. Coccu.s and Pulvinar!% scales re not easily separated. Lecan1um scales differ from both of these in being larger and distinctly dome- or bell- shaped. Much work has been done with the soft brown scale . However , it has not been the subject of extensive investigation to evaluate its characteristics in Oregon. This work has been undertaken to increase our information on the local habits of this scale, and to investigate the effect of some chemical controls . ECONOMIC IM ·ORTANCE The soft brown scale 1s one of' the most common 3 scales to be found in Oregon. lta host range includes many of the bro dleaf evergreen trees and shrub {19 , I p . 36) . This scale is a potential threat to cro s throughout its wide range, but it is generally con• sidered of secondary importance. Writers all over the world cite isolated instances where acute damage has occurred as a result of the activities of th1 scale, but most believe that generally the action of p ras1tes keeps it under control ~ In important fruit growing district 1n Peru, the soft brown scale occurs on mango but is not of economic importance due to the fact tha t it is controlled by natu ral enemies (30 , p . l20) . In Palestine this scale is cons idered the most important economic pest on citrus (16 , p . 325); however , when the population increases 1n May and June , natural enemies also increase and tend to control it. In valifornia, Quayle reported that the soft brown scale is usually restricted to isolated trees , and infestations generally disappear quickly due to the work of parasites (15 , p . l4) . These reports are typical of those found in the literature. In summary it appears that Coccua hesneridum L. is generally of secondary im port~ce due rimarily to natural enemies and becomes of major importance only when some factor upsets th1 natural s1tua.t1:on (31J¥!l •820), (10 , p . 711) and 4 (6' p . 593) . An example of the damage iihich ca n ooeur due to, soft bro\m scale aot1v1ty was indicated in a paper by Ewart and Elmer concerning their work in California (8• P•352) . Of the several unarmored or soft s cales which a ttack citrus trees in California, t hese authors lis ted four whleh t b.ey consid-ered of most 1mportano,e,: ::7·a1sset1a oleae (Burm . ), t he black s ca l e ; Cocoqs paeudoma.BJ10l1arum (Kuw .. ) , the c1tr1cola. scale; Icerfa J2Urches1' f.1ask . ; t he cottony cushion s oa.le; and Oo.cous heaperigum L. , t he soft brown seale. These authors have indicated t hat Coccus hes neridum was generally controlled by natural enemies .. Despite th1s f a.·ct, 1n:teetat1ons occasionally got out o·f hand and damage quickly resulted. and eo.onomie. . ' Ewart. Elmer did their work where infes t a tions of these scales were severe enough that cop.trol measures were needed. As a result of their control of these s cales the fol• lowing increased fruit yields occur red in each citrus plot: 16 .1- 75 . 4% fpr c1tr1oola scale on navel orange; 26- 751l f or cottony cushion so~le on navel orange ; 4 . 2 17. 2% for soft brown scale on navel orange; and 18. 4• 61 . 4~ for soft brown s cale on gra efru1t. Consideration of th& data presented here leads to t he eonclus1oh that th~ .soft brown, scale 1a a potent1al 5 enemy which can increase to economically important populations. Oregon has a 9 150,000 annual holly crop (17 , p . 3) . With this crop to protect, workers should be ware of the presence of this pest and be on the alert for its increase. DI STRIBUTION, HOS ~S AND INJURY This scale is important for several reasons . Two of these reasons are its world- wide distribution and its broad host range . &• hesnerldum occurs on a wide va riety of greenhouse and ornamental plants and fruit trees . The follow1ng list i s representative of the host types involved (7 ; p . 288) and {19 , pp. 36-37} . abut1lon fig morning glo~y aloe gardenia mulberry apple grape myrtle pr1oot grapefruit oleander arall1a guara orange e.ra.ucarta hawthorn orchid ash hibiscus peach avocado b,olly pear azalea. India rubber phlox banana English ivy p1ttosporum bouga1nv1lla.ea j a.ami.ne plum boxelder kentla palm po1ntsett1a boxwood laurel poplar camellia. California laurel prune cassia. lemon rose cinchona locust sago palm citron madrone sterau11e. clematis magnolia strawberry tree date palm mango water hyacinth ferns mo.nza.nita willow facourtia maple 6 One way in which the soft brown scal e mi ght cause losses to t'be commercial grower i s to be present 1n l arge enough numbers to make a pl ant unsalable or useless for d i splay purposes . Contributing to this gener al condition of uns i ghtliness a r e other f a ctors such as excessive honeydew accumulation and the accompanying sooty mo ld (.commonly Fumago vaga.ns or Ca:pnodiy.m footi) (4 , p . 359) . This sooty mold i s not only uns i ghtly , but may disrupt physiological activity in the plant. In the event of a serious infestation, plants tend to be less thrifty and could even be killed in time by an extended period of reduced vigor. TAXONOMIC STATUS AND DESCRIPTION TAXONOMIC POSI TI ON There has been a divided opi n ion concerning the taxonomic position of the soft brown s ea le and this is still evident in current literature. Regarding the hi gher classifications of super family and family , the writer has adopted the position originally suggested by Ferris and advoca ted by Stein weden (20 , p . l97) . These authors treat the soft brown s ca le as a member of the superfamily Oocco1dea , family Coeoida e . 7 Generic classification bas probably been even more confused than the higher class1f1c t1on. The soft brown scale w named Coccus hesperidum by Linnaeus in 1758 {12 , p . 445) and is the type of the genus Coccus . Not only has this genus been frequently placed in the family Lecani1dae {Lecano1dae) (3 , p . l8) , but also the species has been placed in the genus Lecan1um (13 , p . l78), (11 , p . l 88 ) nd {23 , p . 206) . The latter classification for the soft brown scale prevails 1n the most recent of publications , including that of Brues , Melander and Carpenter, "Class1f1c tion of Insects•• {2 ' p . l65) . The writer is using the scientific name of Linnaeus (12 , p . 445) . It was used by Fernald (9 , p . l68) and adopted by the merican As oc1at1on of Economic Ento mologists (14 , p . l30) , namely CocQY! neaperidum L. This also concurs with the view of 3teinweden (21 , p . 563) . le dealing with the subject of names , it ia convenient to consider the status of the common name . The writer is not using the name '1 soft scale'' as do Mueaebeck (14 , p . l30) and Fernald (9 , p . l68) , but is 11 using the name "soft brown scale • This scale is nown quite generally as the soft bro'm scale and this name has been used in innumerable publica tions . 8 Since the general group to which the soft brown ~cale belongs 1s known as the soft scales·•. 1t seems only to add confusion to the issue to change the common name of this species from that whicb is generally accepted 11 to the usort eca.le • To summarize the position of the soft brown scale as treated 1n this paper', the classi:fi.ca.tion ia as follows: Ooocoidea , Coccidae, Coccus hesperidum L. SYNONn!Y The following list of synonyms was taken fro Cancela da Fonseca (3 t p .16; 17) With tl-10 mad1f1c tiona t a reference was added from Fernald's catalogue (*) (9, p . l69), and those references which were cited from works previous to 1758 have been omitted. Coccus hesper1dum L1nn . The Soft Brown Scale 1758--Cocous hesper1dum L. , Syst . Nat•. , Ed . x , I, P • 455 . 1762--Chermes hesper1dum Geoff , ii t. Abr . Ins • , I • p • 505 • 1835--Clypticus hesperidum Costa , Faun . Reg . Nap ., Coco ., p . 8 . 1835--Calypticus laev1s Costa , Faun , Reg . Nap •• Co co., p . 11 . 1835-- Calymnatus hesperidum Costa, Nuov . Osaerv .. , P• 22 . 1835--Lecanium hesper1dum Burm ., Hand . Ent. II; P • 69. 1843--Cocous patelliform1s Curt., Gard Chron., P • 517 . 9 *1867--Chermes hesper1dum Bdv . , Ent. Hort,, P• 331 . 1867--0hermes laur1 (Bouche) Bdv . , Ent. Ho rt. , p . 340 • 1870--Lecaniu platycer11 Pa ck ., Rep . J. ss , Bd . gr., P• 260 . 1873•·Leoan1um angustatum Sign . , Ann . Soc . Ent . Fr. 5(3):398. 1873--Leo nium 1aur1 Sign., Ann . Soc . Ent. Fr• 5 ( 3 ) : 400 • 1873--Lecanium macu1atum Sign., Ann . Soo, Ent , Fr. 5(50):400 . 1875--Chermee auran~11 Alt., Tr t . Col . deg . Agr., p . 431. 1886--Lecani al1enum Dougl . , Ent . Mo . Mag . , 23:77. 1887--Lecanium tesselatum Dougl ., Ent. o . Mag. 24:25. 1887--Lecanium depressum var. 1mulans Dougl ., Ent. Mo . Mag . 24:28. 1892--Lecanium minimum ewst., Ent . Mo . mg . 27:141 . 1893--Lecanium assimtle var . amaryl11d1s Ckll., · 'l'ra.ns . Am . Ent . Soc. , xx , p . 53 . 1893--Lecanlum term1na11ae Ckll., J . Inst. Jann. !:254. 1895--Lecanium ceratontae Genn . , Bull . Soc . Ent . Fr. 7(5):CC XVII . 1896-- Lecanium hesper1dum var. 1aur1 Ckll ., Check List , P • 331 . 1896-·Lecanium nanum Ck11., Psyche , VII, Supp1 ., I. P • 19. 1897--Lecanium flaveolum Ck11 ., Psyche 8:52- 53 · 1897--Lecanium minimum va.r . p1n1oola Mask., N. z. Trans ., XXIX , p . 310 . 1898--Leca.nium ventrale EP.Th ., Canad . Ent . 30:2~5 . . t 1899--Lecanium calymnatua var. p1n1cola Ckll . & P~rr ., T~e In~ustrial1st , p . 230 . 1899-- Lecanium h.esperidum var. alienum Ckll .. , Checlt List., . p •. 393 . 1902•- Leca.nium {Calymna.tus) hesper1dum var. . pa~1f~oum Kuw ., J . N. Y. Ent. Soc . 10:30. 1903--Coccus (Lecanium) m1n1mus Ckll ., Ann . Mag. N. H. 7 (11):162 . 1903-- Coccus angustatus Fernald, Catal . Coco • . World., p . 168. · 1903--Coocus flaveo1us Fernald, Catal . Coco • .. World p . 168 . 10 1903--Cocous heaperiduo var. alienus Fernald. Cata.l . Coco . World , p . 171 . 1903--Coccus hesperidum var. lauri Fernald, Oa tal·. Coco·. World , p . 171 . 1903--0occus hesper1dum var. p"'cif1cus Fern ld, ' Ca. tal·. Coco. World , p . 171 . 1903--Coccua ma.ou atus Ferna d, C tal. Coco .. World , p . 172 . 1903 -- 0occu~ m\nimua Fern ld, Oatal . Coco . rlorld , p . 172. 1903--Coocus m1nimus var. pin1oola Fernald, Catal . Coco . World , p . 172 . 1903--0ooous ·nanus Fernald, Catal . Co co . World, p . 172. 1903--Coccus terminal1ae Fernal d , Catal . Coco . World, p . 173 . 1903•-Cocous ventr lis Fernald. Ca.tal . Coco • . World , P • 174. 1903--Leoanium heaper1dum var. minimum Newst ., • on. British Coco ., II, p . 85. 1904--Lecanium sign1ferum Green, The Cooc1d~e of Ceylon, III, P • 197. 1906-- ? Lecanium (Trechocorys) hesperidum var. afr~canum New s t . ·~ (sine descr. ) Liver pool Univ . ~ua.rt . J ., I; 2, p . 74 . 1908-•? Lecanium hesperidum var. javanens1s Newc t ., J. E,oon . B1ol . III, 2, • 38 . 1909--? Coccus hesperidum var. javanensis Stand., U. S . D. A., Techn. uer. 15 (III):45 . s shown in the section on the taxonomic position ot Q. heaper 1 du~ and lao 1n the foregoing list, con s i derable confusion exists in the 1dent1f1cat1on of this insect. Sanders (18, p,433), for example , has given these reasons for th1o confusiont this seale exhibits great variations in size, color, and markings ; 1t has been of exceptional importance to horticulturists and gardeners; it has a widespread distribution nd great range of food plants. These factors coupled ll with t he fact that early wo r ker s u ed inadequate char acters for cla.sstf:tcation are renson enoue;h for confusion. The "' e reasons a. re quite valid as evi denced by the work of Ebeling on Lecanium corn1 Bouche . another soft or unarmored scale. Ebeling succeeded ln trans ferring t hls scale to a oer:tes of difterant hosts and noted extre-me b.oet..,determ1ned morphological vari ability. To this factor he attributes much of the synonymy of L• co!!!!. (5, p . 6Z9) . .Q_ . hesner1d.ym and 1 · corn1 are both soft s ca les and share many s1mi·la.r1ties . It 1$1 ~ probable t ha t similar factors a~e at work in both cases to obs cure t he i.dentity of t hese scales. DE >3 CRI PTION ' ' l?erhaps the mos t ·d1·11:gent effort to find better characters for 1dent1f1eat1on and classification of this scale 'lflas by J. B . Ste1nweden (20 , pp. l97..205) and. (21 , pp . 561- 571) who .worked under a. F . Ferri·s . a noted s ca le authority . The following t axonomic de scription of the aoft brown s ca le \~as taken from one of ~ teinweden ' s papers. (21 , p . 563) . Adult female: ••• Flat, naked, oval in shape , variable in size, from 1. 5 to 5 mm . in l engtu; usually yellowish brown in color, al though at times gr eenish and marked with darker hues . Antennae ••• seven-segmented, third and fourth segments longest ·. Legs ••• well deve• 12 loped, Tit out free tibio- tarsal articulat on, with merely transver e septum between the tibia and ta.r..;uo, and pp rently no free movement of the joint. nal cleft relatively short. Anal plates ••• ncarl ~ua rat6- shaped, but with the caudo- latex·al ma.r ins slightly longer t an tno cop lo- latera.l margine, the lateral angles moder tely rounded, and the apices pointed. ~ach plate with four apical, two subapical, two fringe setae , and no di cal or hypop3 g1al et .e . Jlobdo inal se.... ent t 1on lacking. piracles normal . larr1nal setae fairly short , slightly curved, ointe or slightly fimbriate at tip. Three stigmatic etae ••• , the middle ono lone , dully pointed and slightl y curved t the tip, the other two short and pointed . A f &hort body setae scattered over dors~ nd venter, three pair& of long , slender net e on the abdomen in front of the anal plates , one short and one longer setae near the bas of each antenna . 0t1g ma.t1c depressions indicated by sl1. ght depression 1n the body contour. A few am 11 , simple round pores cattered over the dor··um • • • • A relatively small number ••• of mult1locul r pores in the ventral an 1 resion ••• 6-10 small ub-marg1nal tubercles •••• a single row of quin~uelocular pores in each ·t1gmat1c furrow ••• ,. No tubul r ' duct resent. D ~~ C iUPTION OF STAGES FIRc-· T I .. TAR The y llo -brown to brown , dorso- ventrally com ·~ pressed body uf the first 1nst r or crawler stage , (Eigure 1) of this cale is essentially ovate and may · taper slightly caudad . The eyes consist of two small apots far forward and on the 1 teral margins of the body . 11 the major appendages are on tha ventral 13 surfa.c of th scale . The lees and antenna.e roject to the oidos beyond tbe edge of tho body . Legs . antennae, · nd piercing mouthp rt£, !lre all 11ell devel oped . The ~ ntennae or1g1n~te at points just b ~aind a 1 ne 1 r~ m thr ugh the eye,.. nd s igl tly in a medial direction from the eyes . They then project laterally and f rwa. in a 1ne just anterior to th~ ~ye spots . The sucking mouth arts roject from a. mid• lino point just behind the e_oxae of the forelegs . The characteristic anal cleft 1s bounded on each aide by t'"'o tr1ansular plates which are mo st obvious in the dorsal vie1<1 . In the crawler, these plates each bear one very distinct seta which i s a little lese than 1/'3 the body length. These setae oeeur only in the crawler s t age as such a distinctive charac ter. Five or lers were measured and they were f ound to average 0.41 mm . in length and 0 . 22 mm . in width (Table 1)~ \fuen the crawler settles down , 1t inserts 1ts mouthparts and pulls its appendages in under the ca.le ~ The edges of the scnle are then appressed to the sur• face of the leaf ~ The color of the scale may become more yellow, or nt times may appear quite clear and •. 14 colorless . The setae of the anal plates c n still be seen and the s cale grows slightly in size before the first molt . Ten scales in this star-e were measured a.nd found to e.vere.r e 0 . 45 mm •. in length and 0 . 24 mm . in width (Table 2} . TABLE I MEASURE~fENTS OF CRAWLERS IN HILLI't-1ETERZ Crawler ne,. Lenstn Width 1 o . 4o2 0 . 236 2 .· o . 416 0 . 236 3 Q. 430 0 . 236 4 0 . 402 0 . 222 5 0 . 402 0 . 194 Average 0 . 4104 0 . 2248 ~ECOND INSTAR The body .of the second instar nymnh (Figure 2) is elongate- ovate in form . At first this instar 1s also dorso- ventrally flattened, but as growth progresses the middle of the body increases in size. The general outline and contour of the body may vary 1n respons e to the surface upon which the s eale is established• The background color of the body 1s yellow- brown to brown. A variety of patterns may occur which 15 consist of lines formed of minute bro\'in spots . Gen era.lly these lines project from the body edge toward the center for a short distance and tend to form a border around the edge. Patterns may cover the entire dorsal surface . The eye spots are of a aeep contrasting color and occur in the same relative position as in the first instar. TABLE 2 MEASUREMENTS 0 """' THE FIRST INSTAR SETTLED STAGE• IN MILLIM~T.E.'RS Insect -no . Lene;th Width l 0 . 444 0 . 235 2 0 .-471 0 . 208 3 0 . 471 0 . 263 4 0 . 444 0 . 263 5 0 . 444 0 . 263 6 0 . 458 0 . 208 7 0 . 402 0 . 208 8 0 . 444 0 . 222 9 0 . 485 0 . 263 10 0 . 458 0 . 222 Average 0.4521 0 . 2355 There are two pairs of indentations in the lateral edges of the seale. These are the stigmatic deprE\setons . The first pair occurs about as far behind the eyes as the eyes are from the cephalic edge of the scale. The second pair occurs further back. a little before the 16 transverse midline of the body . The anal cleft is deeper, proportionately , the.n in the first stage and the triangular anal plates a t its base lack the distinctive set ae of the first s tage . After many scales were observed t he writer found one second instar individual which had several ~ ssy, transluecent,, gland- like s tructures in a row upon - the dorsal midline of the body. In this individual there were four and evidence tha t others had occurred and had been broken off. Investigation of other scales finally showed t hat there were nine of these protup beraneee , the first three being B?&ced at wider in tervals t han the remaining -six. The placement of these protuberances is doubtless indicative of segmental re lations . Their funct1on. 1s not known to . the writer. Ten second 1nstar individuals \'Ie re measured and they averaged 0 . 92 mm . in length and 0 . 48 mm . in width (Table 3) . ADULT The ad.ul t at first has a background color of yellow• brown and has markings similar to those described for the second instar. Aa the adult progresses to the reproductive stage (Figure 1), the caudal extremities become dark brown on t he ventral surface around the 17 ' reproductive opening . This ventral s t a ining i s also evident from a dorsal view. Th1s detail i s obscured towar d t he end of adult 11fe when the gener a.l body oolor becomes dark brown . TABLE 3 MEASUREUENT:i OF THE SECOND INSTAR IN MILLIMETERS Insect !12. • Length 'W idth 1 0 . 971 0 . 555 2 1 . 124 0 . 499 3 0 . 818 0 . 458 4 0 . 957 0 . 499 5 1 .041 0 .610 6 1 .013 0 . 541 7 0 . 951 0 . 471 8 0 . 707 0 .333 9 0 . 707 0 .388 10 0 . 902 0 . 416 Average 0 . 9191 0 . 4770 The anal cleft, anal plat es ,. sti gmatic depre s 1ons and eye spots ar e more evident 1n t he adult due to its l ar ger si ze, but the eye spot s t end to be obscured as the body color deepens . The legs and antennae are much smaller, proportionately, th~n in previous stages and do not extend beyond the body edge even 1f the scale walks. There 1s great variation in the size of adults. 18 S1x adults were measured immedi a tely after the second eodysts. These scales averaged 1 . 7 mm . in length and 0 . 9 mm . in width (Table 4) . Ten fully matured adults "t ere also measured . These scales averaged 3.1 mm . in length and 1.9 mm . in width (Table 5) . TABLE 4 P-lEASURE fEN TD OF THE ADULT I f.1NED I ATE:LY A. FTEH THE SECOND ECDYSI S , IN MILLIMETER-'S Insect !!2. • Jtength idth l 1. 679 0 . 925 2 1.741 0 . 936 3 . 667 0.970 4 1 . 912 0 . 970 5 1 . 782 0 . 891 6 1 . 542 0 . 719 Average 1 . 720 0.909 I .IFE HtSTORY 1\ND HAD! TS SEASON~L HldTORY Observations on the life history were begun t Tigard, Oregon, on June 25. Field and laboratory observations at this time showed that the winter was passed by adult and second tnstar soales . First tnstar scales were not present. Adult scal es had 19 begun to reproduce by this d t e and the resulting crawlers were still confined beneath the adult scales . TABLE 5 }I ASURE!·1ENT:J OF THE FtJ LLY- 1~ TURED ADULT , IN MILLIMETER£· Insect -no . Lensth Width 1 3 -153 1 . 885 2 3 . 188 1 . 782 3 3 . 256 1 . 885 4 3 -153 2 . 056 5 2 . 913 1 . 782 6 3 . 188 1 . 714 7 2 . 875 1 . 885 8 3 . 050 2 . 022 9 2 . 845 1 . 714 10 3 . 359 2 . 571 , Average 3 . 0980 1 . 9296 After the liberation of crawlers from under the adult s o 1es in early July , all stages of the s cale wer e present throughout the summer . This w s due to the long period of reproduction exhibited by this c l e , counled with the ability of more than one s tage to pass the winter. Unon finding n a pro riate place to feed, the crawler was found to insert its mouthp rts and settle down . It then entered the s econd s t age of the first 20 instar ~ The edges of the s ca le were appressed to the lea f and the lego were retracted. This had been accomplished in the field by July 6 . The end of this s tage was marked by an ecdybi s which occurred in about two weeks • according to rearing observations . After the large spring group of adults had re produced and died, t he smaller s t age of the scale we r e predominant on the foliage . · dults were then found less frequently. On September 17·, samples were t aken and the m jority of. the s ca les were s till in the second 1ns t ar . Some s ca l es had newly turned dult a t this time . tiome crawlers were present and re ro ductive adults could be found, thoueh in cons iderably fewer number s than other s ta ges ~ At this time the tra n oition from second to third inet a r wac beginning to t ake pla ce in t he field and on sca les reared out- of- doors . The duration of the s econd ins t a r was 8 to 10 weeks . Thi s insta r w s termina ted by an ecdysis which was s imila r to the f irst. Throughout t he remaining ob servations , the ca les did not s eem to change markedly in the f i eld or on rearing pl ant s out ! de . Observa tions on Octbber 6 in Tigard s till showed a predominan~ numbe r of late second instar nd youn g adult 1nd1v1du l s . Large 21 numbers of smaller scales were also in evidence. Reproductive adults were few in number. On November 19 t ob ~e rvations in Tigard showed that some scales still had crawlers beneath them . but the main gr~ up of scales still existed either in the second instar or young adult condition. Observa tions on December 8 in Ti gar d revealed little change . Adults were still able to produce cra\'llers , but \then cr wlers were uncover~d their movements were found to be very feeble 1n contrast with earlier observations . \ihen the last obs~rvations vrere made on reared scales outside on December 6 they were in a young adult condition. No reared snecimens had reproduced . It i s clear from these findings tha,t the ooft brown scale in Oregon had only one generation this year. BIRTH OF' CRAWLERS Laboratory observations of ~he adult female on June 25 have shown this scale to be ovoviviparous . The observa tions oame from a femal e s oa l e which con tinued to reproduce a fter it was turned on its back. Three scales were born during this inspection, the first t·o emerging head first and the third with the posterior end first . l~e crawlers were enclosed in a thin membrane at birth, but details such as eye spots 22 were easily seen. Th young sca les broke this membrane by swelling the cephalic and caud 1 ends and by peri odically arching the body . ~lapsed time from beginning of birth to free1ns of the appendages was 19 minutes for the first scale nd 14 minutes f or the ··econd . Com lete freedom of movement wa s attained in 38 minutes for the first scale and 29 minutes for the second . These ca les were liberat ~d continuously from t he re productive opening , one being delivered while the one previous was still struggling to free it appendages . The three scales obs erved were out of the femal in a period of 30 minutes . The las t aot in this process wa the dro ping of the membrane in which the scales were born. This membrane then had chara cteristic Y shape . From these observations it is clea r that the Ghedd1ng of the membrane took place quickly L~d the fully formed crawler emerged . F!i:CUNDITY On July 1 , other adults were t aken to the l abora tory and erawl~rs to be used 1ri .rear1ng work were removed from underneath them . These crawler were established on 20 holly ulants (~ agu1fol1um var. 23 Rederly) . Ten of these plants were kept in the green, house and ten outside . Sev~ra.l crawler s were established on five leaves of each pla:nt.. Baffles were placed around the petioles to isolate crawlers until they could establish thems elves . 'Thes e baffles were sealed w1 th •• ~ree - heal n and coated with "Tanglefootrt • When crawlers had settled they were thinned to one per leaf. Crawlers occurring under adUlts were counted as the:y; were removed from each scale . In 60 such observations each fem ~ le covered an average of 17.8 crawlers. The maximum number pf crawlers from any one scale was 39 . Fecundity data were taken from the scales reared ln the greenhouse . Reprod.uctlon began 80 to 85 days after the ·crawlers were introduced in the greenhouse . The highest number of crawlers produced by one in dividual was 149, produced in 38 days; second, 107 in 11 days; third, 94 in 23 days ; fourth, 73 in 25 days; fifth , 60 in 38 days. Nineteen others produced an average of 16 individual s in the course of these observationa. 'i'he highest f1gure i s perhaps the best indication of the actual order of fecundity since the action of parasites disturbed the reproduction of other s ca les. After becoming adults. , scales did not reproduce immediately. There was a. period of f3' rowth during whioh 24 tne adul~ about doubled its dimensions . t some point durin this growth the scales be ~an to r enroduce. Though there are reports in the literature of males having occurred (3, p . l04), this s ecies is generally considered to be parthenogenetic . The writer found no evidence of males duri~ his observ tiona . OVEJ·mN'T OF CRAwl.ERD AND 1\DULTS On July 6 , oboerv tion .at Tigard showed that the crawlers had been liberated from under the adult scale and had moved to the new growth. At this same time it w s observed th t some adult had succeeded in moving to the new ,growth. All stages of the scale. exoe t perha~s the post- reproductive adult were found to have the ability to move . DIDPERSAL During the early s ray trials at Tigard, the orchard was surveyed for infested trees upon which to apnly controls. This was before the spring brood of crawlers hatched. When trees were selected, it was observed that trees in several of the adjoining rows were free of infestation. Inspection later in the summer howed these trees to be infested with young scales . This infestation could not be attributed to 25 hatch on the tree, since a population sufficient to e au se it had not been there previously. In view of these findings it wa s decided that crawlers had been blown to these new hostrs by ·the wind during the hatching period of the spring brood. l-10LTING The beginning o f an ecdysi s was not easy to determine and th~ writer found no way to establish the initial change . The skin was apparently severed some where along the anterior portion of the body before being withdrawn to the rear. The first di"' tinct1ve s1p:n of change observed was when the shed skin began to ppear t the caudal end of the scale . This skin appeared in t he region of thg anal cleft from under one side of the body and was found to remain attached to the new insta.r for days or weeks . Leg and antenna.l characters were observed 1n the shed skin and 'th~ remainder was shriveled . TEMPER~TURE RELATI ONS The writer determined the departure from normal of the monthly average temperature 1n Corvallis for the July through I;ovember period. Th1s was also done for temperatures at the experiment site. Then these 26 monthly tem erature departures were averaged for both stations. Granger station (official for Corvallis) showed an average departure from normal of -2 .1 5 ~ F for this period while the experiment site showed an average departure of +1°F . · Temperatures t the rearing site were higher than normal due to the fact that this site was in shel tared area bounded on three sides by greenhouses. The verage t emperature• at the rearing site fo:r the eriod covered were above local normals , even though this was a colder than normal period. Sinc e this is true, not much departure from the one generation per year cycle of this scale should be anticipated. In the t ble of temperature do. ta (Table 6 ) , per sonal data e compared to weather bureau records• most of which \:ere found in ''Climatological Data" {24 , p .145,146) ., (25, pp . l59,160), (26, p . 83 , 84) , (27, pp . l03,104), (28 , pp . l17,118) and {29 , pp . l33, 134) . Di vCU St.ION There are two difficulties connected \fith attempts to accurately determine the duration of the first instar. First, it is difficult to determine when the molt 'vh1oh termin· tea the instar begins . .d econd , the 27 crawlers remain for a period un~er the parent seale . The writer originally intended to lift adult sceles daily to check f or nroduction of crawl er s , but the scales did not respond well to such treatment. It has been indicated that not muc h departure from the one r eneration cer year of this insect would be anticipated . This i s the expected average perform ance of this scale. In warmer years it may be ossible for a partia l second generation to occur.. CONTROL SOFT BRO\iN SC LE Na tural conj:rol.. The writer ha.e already treated the subject of natural control to some extent and indicated tha t it i s of the utmost importance concerning the soft brown scal e.. Observations in the f i eld conf irmed t he_ fact that parasites a re abundant, since post-reproductive adults were al most always found with emergence holes in them. During one series of observa tions , t he writer found two seriously infes t ed trees i n an orcha r d in t he Corvalli s area. \·hen first observ ed, these scales were all young adults •. It was the writer' s intention to make additional life history observa tions here . However , t wo weeks l a t er not one / TABLE 6 COMPARISON OF 'TEMfERATURE DATA FOR EXPERIMENT SITE AND CORVALLIS FOR Tiffi PERIOD JULY 1 TO NOVlli~CR 30 Month Station Ave., Ave. Ave. Depart. No. of -Dazs Max. Min. from Ma• . ab ove Min. below normal 90° 32° July Corvallis* 76.1 49.4 62.8 -3.4 0 0 Expt. site 82.9 49.1 66.5 +0.3 4 0 Aug. Corvallis 76 ~0 50.1 u·l -3.. 1 0 0 Expt. site 79.1 50 .3 .7 -1. 5 1 0 Sept. Corvallis 72-~ ~6~2 69-3 -1~7 0 0 Expt. site 76. 47-3 2.,0 +1.0 l 0 Oct . Corvallis 61.3 ,7~6 50~0 -3~6 0 8 Expt. site 64.2 2.7 53- 5 -0.1 0 0·-'·* Nov. Corvallis 51.5 41.1 46.3 +1~2 0 2 Expt. site 56.? 45.7 51.2 +5.8 0 0 *Weather bureau figures :frot:l "Climat ological Data" for Corvallis, State College station (Granger). October and November figures from weather bureau data not yet published~ 1 ->H;-Thermograph recorded only to 40°F • Note 8 days below 32°F for o:ff icial data. 1\) ()) 29 adult could be found which had not been killed by parasites . Reporta from all OV 8r the world claim effective parasitic co11trol for the soft brown seal e and w. R. Thompson ' s catalogue of parasites and predators (20.1 pp. 35,36) lists 34 species of insect which attack this sc-:lle. Chemical control . The f1rst attempt to control soft brown scale was at Ti gard on May 27 . In tb.is trial two trees were used, one sprayed. and one as a check. Ten leaves on each tree were chosen and marked . Counts of living scales we re made on these leaves before and after treatment. The scales were in the adult stage and had not produced the sprlne; brood of nymphs . A 59% malathion emulsifiable concentrate ;', ~j • was used a t the rate of l~ pounds of actual toxicant per hundred gallons of water:_. Triton 19 6- B emulsifier ' was added at the rate of t pint per hundred gallons of water. Application wa s made with a Bean power sprayer mounted in a pickup truck. From May 26 to June 11 the total number of 1n d1vidualo 1n the malathion plot for 10 samples wae reduced from 47 to 1 . The number of scales 1n the check ohaneed from 53 to 52 . Using Abbott' s formula 30 the corrected figure for percent control wa s 97.9~. The next spr ay wae applied a.t Ti gard on ,June 25. At this time crawl er s were beneath mo at adult s ca les and few had emer ged . 'fhis teat was s et up in a manner similar to t he f irst in tha t a check and spr ayed tr~e wel"e used . Ten l eaves Wet'>e marked on which living s cales were counted before and after trea tment . This plot wa s sprayed with. a malathion 59~ emulsifiable concentrate at the rate of l t -poundo of a ctua l toxicant per hundred gallons, of water. Triton 1956-B emul s ifier was added at t he r a te of i pint per hundred gallone of water. ·copper sulphate wa. s added at the r a te of 2 pounds per hundred gallons of water. Application was with the Bean sprayer. Soon after the application of this s~ ray t he condition o f othe r trees in the orcha r d became a matter o f concern to t he grower. On July 16 the grower applied a genera l spr ay to o. major portion of the orchard. Thi e anplioation cove r ed t hat of t he writer' s June 25 applic a tions . The grower's application rates were similar to t he wr1ter•s , never-the - l ess this compl icated the takine of records because the check lot wa s now opr ayed_once and t he spray plot had two applica tions . La ter in t he year the writer f elt that some me thod should be devised to obtain some data on 31 the effect of these sprays. Therefore• on October 6 , 100 leaves were taken tn e.s near a random manner a.s ' possible from both the spray and check plots and also from trees higher in the orchard which had not been sprayed by the grower. t,1v1ng s cales were counted in each sample of 100 l eaves . In the sample which wa s sprayed twice }0 s c ales survived. In the sa~ple sprayed once 240 scales survived . In the unsprayed sam:ple 720 11v1ng s c a les 11rere fotm,d . Liv1ng scales were reduced from a.n average of 7. 2 scales per leaf to 2 .4 acaleo er leaf by one application of spray . They were reduced from a.n average of 1 .. 2 scales per leaf to 0 . 3 scales per leaf by two applications . On October 27 another spray application was made in the Tigard orchard. In this trial malathion, chlorthion and check plots were used. 4ala.th1on and chlorth1on were both used at. the rate of li pounds or actual toxicant per hundred gallons of water. Triton 1956- B emul s ifier was used with each at the rate ot ~ pint er hundred gallons of water. Application was made with the Bean power sprayer and a hand gun . In this trial• five leaves were marked per tree. Living scales were counted on these leaves before and after treatment. Plots were replica t ed four times . Abbott' s formula was used e.s a correction in evalua tion 32 of the results . In this trial mal a t hion gave 84 . 7% control and chlorthion gave 28 . 2% control (Table 7) . The results ith these insecticide s 1n t hi s trial were r el atively poor which probably was due to the cold eather during this period. Lli'CANI UM In t he same orchard t Tigard. Oregon where the spr ay trials f or t he soft brown s o l e were applied, a section of the orchard was f ound to be heavily infested with a Leca n1um cal e , Lecan1um sp. 2 This i nf eB t a tion wa s chiefly on variegat ed holly . Though t here was some contamination with soft brown s cale, the roport1on was small enough for the tes t to be represented as a control for Lecanium (Fi gure 3) . In this tes t t here were f our treat ment s , which were mal a thion, chlorth1on, lindane and check. These were applied i n four re lica t e s . Five leaves were mar ked on each tree and living s c ~ le s were counted on t he se leaves bef ore and after a plication. A lica t1on wa s made on September 1 . Mal a t hion and c hlorthion were apPl i ed a t t he r a te of 1 pound s of a c t ual t oxicant per hundred gallons of wa ter. The 2 . See footnote one . 33 TABLE 7 COI4P \RISON OF MALATHI ON o\ND CHLORTHI CN FOR CONT ROL OF COCCUS HESPERI DU11 ON HOLLY, TI GI\RD , OREGON • 1954 •. Malathion Living Scales Reps . Oot. 25 Deo . 8 **Percent Control 1 *16 . 2 4. 8 2 11 .6 1 .4 3 2} .6 1 . 4 84 . 7 4 12 . 0 0 . 4 Tot . 63 . 4 8 . 0 Ave . 15 ~ 85 2 . 0 Chlorthi on 1 12 .6 9 0 2 15. 8 9·8 ... _ 28 . 2 -·- ' l'' '4 , 10 . 2 4 . 0 Tot. 38 . 6 22 . 8 Ave . 12 . 86 7 .6 Check 1 19 . 6 15. 4 2 21.6 18 .6 3 13 . 8 10. 8 4 15. 2 13 .0 Tot. 70 . 2 57 •.8 Ave . 17 . 55 14 . 45 *Each figure represents the average of living sca les per leaf for 5 leaf samples . **Percent control corrected by Abbott's formula. r a te of lindane application was 3/8 of a pound of actual to icant er hundred gallons. Triton 1956-B emulsifier was used in all cases at t he r a t e of t pint 34 per hundred gallons of water. Application was with the Bean power sprayer and a nand gun. In this test malathion gave 99.1% control , chlorth1on gave 94 . 9% control and lindane gave 89 .1% control (Table 8) . PULVIN:\RI Ea rly in the spring camellias a round a church in Corvallis \i'ere found to be heavily infested with Pulvtnaria flooc1tera (West.)3 , the camellia scale. These shrubs also had a dense cover of sooty mold . Tes t s to control this s cale were ca rried out on these shrubs . The scales were 1n the adult s t age and the egg masses were not produced until fter the comolotion of this trial . A prelimina r y test was made on two of these shrubs on May 13. One shrub was used for spray and the other as a check. l·1alath1on was used at the rate of 3 pounds of actual toxicant per hundred gallons '\'Thich was double the usual dos~ge. No sticker wa.s uaed in thls trial •. Appl1ctlt on we. s made with a small Hudson power sprayer and. a hand gun. Ten leave3 ·ere chosen on ea.ch bush and marked. L1v1ng scales were counted on these .leaves before and after treatment . In the cheek, the number. . · ' ,, • ·i _, Tentative determ1natio~ 9~ ·n,;.' ·a.. Morrison""t··ae*e · ; footnote one) . 35 TABLE 8 COl4P ~ RI Z ON OF THREE IN ciECTI CIDF.S ~oR CONTROL OF LF.C\NI UM N~·WHS ON HOLLY, TI GARD , OREGON , 1954 Malathion Living Soales Reps. Sept . 1 Oct • . 6 **Percent Control 1 *13 .0 o.o 2 14.6 0 . 2 3 8 . 6 o.o 4 19. 2 o.o 99.1 Tot . 55 . 4 0 . 2 Ave. 13. 85 0 .05 Lindane 1 14. 8 1 . 2 2 21 . 0 o.o 3 37. 4 1 . 8 4 16 . 8 1 •.o 89. 1 Tot. 90 . 0 4 . 0 Ave . 22 . 5 1 •.o Ch1orth1on 1 34 . 0 o.o 2 19. 0 0 . 8 3 11. 2 0 . 4 4 14. 4 o.4 94 . 9 Tot. 78 .6 1 . 6 Ave . 19. 65 0 . 4 Check 1 19. 6 7 . 4 2 17. 2 4 . 6 3 17. 8 8 . 6 4 16.2 8 . 2 Tot. 70 . 8 28 . 8 Ave . 17. 7 7 . 2 *These figures represent the average of living s cales per leaf for 5 leaf samples . **Percent control corrected by Abbott' s formula . 36 of scales was reduced from 71 to 11 individuals.. In the spray plot the number of scales wa s reduced from 189 to o. The reduction in the check in this trial wa s attributed to the effect of spray drift. This test resulted in 100% control . When the last check wa s made, the writer wa s unable' to find any reinfesta.tion of scales . The test jus t described wa s followed by another on August 31 .. Six o,ther shrubs: in the same planting were used . When this test wa s applied, adults had reproduced and died . The immature forms were present at this time (Figure 4) . There were three treat ments , two replicates used per treatment . The treat ments were malathion, chlorthion and check. la.th1on and ehlorthion were both used at the rate of lt pounds of actual toxicant per hundred gallons of water. Triton 1956- B emulsifier wa s added at the rate of pint per hundred gallons of wa ter. The sprays were applied with a knapsack type sprayer. In this test malathion gave .99% control and chlorthion gave 97% control (Table 9) . '37 TABLE 9 COMPARI SON OF MALATH I ON AND CHLORTHION FOR CONTROL OF PULVINAR! NYMPHS ON CAMELLI A, CORVALLIS , OREGON , 1954 Malathion Living Seales Reps . Aug . 27 Oet . 6 Percent Control 1 *39 . 4 0 . 8 2 41 . 5 o.o 99 .02 Tot . 80 . 9 o.a Ave . 40 . 5 0. 4 Chlorthion 1 51.8 2 . 7 2 39 . 8 0.1 96 . 95 Tot . 91 . 6 2.8 Ave . 45 .8 1 . 4 Check 1 42.6 71 . 3 2 49 .1 43 . 0 Tot . 91 . 7 114. 3 Ave . 45 . 65 57. 15 *These figures represent average s cales living per leaf for ten leaf samples . FUNGICIDE COMPATIBILITY Applica tions were made during the summer to test the safety of mal athion on holly pl ants and a l so to test its compa tibility with fungicides . Two applications of malathion were made at different times a t the rate of 3 pounds of actua l toxicant per hundred gallons of water. This dosage 1s twice that which i s necessary. 38 'nhe ap lications \fare made on two trees at the entomology farm . The first application w s made on A r11 20 before tne appearance of new growth. The s econd was applied to tho nQu growth on June 26 . ~either of these t ests resulted in d mage to the holly . Other tes t s were made on July 26 to tes t the compatibility of m lathion ·tth copper sul h te and with dithane D- 14. In each spray malathion 25t wettable powder w s anplied at the rate of 1 pounds to 100 gallons of w ter. Each spray also contained Triton 1956-B emul sifier at the rate of . pint per hundred gallons . The first spray contained copper aul hate at the r a te of 3 pounds per hundred gallons . The second r y contained dithane D-14 at the rate of 2 qu rt per hundred gallons . Each of these sprays w s applied to about 50 feet of holly hedge at the . College•s Lewis-Brown farm . Later examination of these plants showed no injury. DI SCU .:>G ION \ihere s rays were directed against adult and i mmature forms of the scale as in Pulvinarta and Coccus, there was little to indicate that timing made much difference as far as percent ge of control of 39 individua l s is concerned. Sprays applied during the summer killed the different s t ages present with equal effectiveness . Te sts show that s r ays work bett er in the warmer part of t he s eas on . When spr aying for control o:t' the soft brown s cale, the grower i s f a c ed with the f a ct t hat all s tages are present a t all times during the summer . Sprays seem to be just as effective agai nst a.dultn and nymphs , but crawlers can survive under t he protection of the adult body . This was obs erved in samples t aken from the soft brown s cal e spr ay plots . Crawl er s under adults were killed i n some ins t a nces and were not killed in others . Extra sprays may be necessary to kill young s ca les emerging from adults which escaped treatment as well as those tha t mi ght survive under dead. adults . The Leca.niurn s cale may' be controlled at any time after the e ggs hatch and before cold wea ther occurs . This scal e was f ound in t he spring in the e gg s t age . The eggs were cover ed by t he dead shell of the adult body . The ha tch o,ccurred within a short period of time in Augus t , leaving the youne vul ner able through the res t of the summer and early f all. Pulvinaria .flocctfera. apparently wintered here in the adult s t age . Frothy egg masses (Fi gure 5) were 40 produced about the l a tter nart of J une. In thic cnee it would be advant ageous to spray the adults in the a rin before the production of egg masses . If this period i s passed , however , egg hatch in ,. e:.hort eriod of time and a ll t he young r e soon established and are then susceptible to spray throufhout the summer . SUMM~RY Biology investig tiona were carried out on the soft bro~ e c ~ l e , Coc cus hesperidum L., during t he summer of 1954. These investi gations were centered at Ti gard, Oregon to determine s ome of the habits of this scale i n the illamette valley. Holly ~a.s the host plant . In Ti gard the winter was pa£sed by second ins ta.r and adult s c ales . Reproduction began by June 25 and crawlers were liberat ed from under the adults by July 6 . All s t ages of the s cal e were continually ureoent from t hi s point on until the l ast obs ervation on December 6 . Scal es were r eared in Corv 111s beginning i ith crawlers of the i... pring brood co1lected July 1 . The soft brown s cale passes through two instars and becomes adult . Rearing observations ohowed the first instar to las t about t '\vO weeks and the second eight to ten 41 weeks. Scales matured in the fall but did not reproduce . There was but one generation this year. Observations at Tigard showed t hat the scales were spread from the mo s t serious area of infestation to a previously clean a r ea by the action of the wind . Sprays were applied to holly to control Coccus hesper1dum L . , the soft brown ocale, and a Lecanium sp. and to c amE~ll i a to oontrol Pulv1nar1a. floccifera ( West ~~ ) . the camellia scale. Rates of application for malathion were li and :3 pounds of actual toxicant per hundred gallons of water. The rate for chlorthion was l t pounds and the r ate for lindane wac. 3/8 of a pound per hundred gallons O·f water. Tests to control the soft brown scale with malathion at the 1~ pound rate resulted 1n 91 . 8 control . In a test which included malathion and chlorthi on at the li ound rate. malathion gave 84 .7% control and ohlorthion 28 . 2% . The relatively poor results were attributed to cold weather. A test to control a Leoanium seale using malathion and chlorthion at the li pound r ate and lindane a t 3/8 of a pound gave the following controls: 99 .1% for malathion, 94 . 9% for ahlorthion, and 89. 1% for lindane. 42 A test to control the camellia soale with malathion at the double strength. 3 pound rate resulted 1n 100% control . nother test comparing malathion and ohlorth1on at the 1 ~ pound rate resulted in 99% control f'or malathion and 97%control for chlorthion. 43 BIBLI OGR _HY 1 . Abbott, w. s . A method of computing the effective ness of insecticides. Journal of economic entomology 18(2):265. 1925 . 2 . Brues, Ch rlea T. , A. L. 1elander and Frank M. Carpenter. Classification of insects . Cambridge, Harvard college, 1954 . 917p . (Harvard college. Museum of comparative zoology . Bulletin. Volume 108) 3 . Cancela d Fonseca, Jorge. Contrubu9ao para o estudo do Coccus hesperidum L. I -Estudo sistematico e morphologico . Broteri 22(49):5- 53 . 1953· 4 . Dodge, Bernard o. and Harold w. Rickett. Diseases and peats of ornamental plants. Rev . ed. New York, Ronald, 1943 . s. Ebeling, Walter. Host determined morphological variations in Lecanium corn,i . Hilgardia 11(11):613- 631 . 1938 . 6 . Elmer, H. s ., w. H. Ewart and G. E. Carman . Ab normal increase of Coccus hesperidum in citrus groves treated with parathion. Journal of economic entomology 44:593- 597· 1951 . Essig, E. o. Insects of western north America . New York, Macmillan , 1938 . l ,035P • 8 . Ewart. w. H. and Elmer , H. s . Effect of unarmored scales on citrus produc~ion . California citrograph 38(10): 352 .. ! 1953 . 9 . Fernald, M ria E. A catalogue of the Coocidae ' of the world . Amherst Massachusetts agricultural college, 1903 . 360p . (Massachusetts . Hatch experiment station. Bulletin no . 88) . 10. Flanders , St anley E . Coincident infestations of Aon1diel1a citrana and Coccus hesperidum, a result of ant activity. Journal of economic entomology 38(6):711- 712 . 1945. 44 11. Green, E. Ernest. The Coccidae of Ceylon. Pt. 3 . London , Dulau, 1904. pp. l71- 249 . 12 . L1nnae1 , Ca rol! . ~ys tem a naturae. Re um an1male. A photogr ph1c facsimile of the firs t volume of the t enth edition (1758) . London, British museum, 1939. 824p. 13. Ma cGillivray, Alex D. The Cocc1dae . Urbana , Scarab , 1921. 502p . 14. Muesebeck, c. F. W. Oommon names of insects approved by the American association of economic entomologists. Journa l of economic entomology 43 L)sll7- 138. 15. Quayle, H. J . Control of citru insects and mites . Berkeley, University of California , 1941. 31p. (California. Agricultural extension service. Circular no . 123) 16. Rivna y , E. The economic status of Cocous hesperidum L. and its parasites in Palestine. Journal of the entomological society of southern Africa 7 : 73- 81 . 1944. (Abstracted in Review of applied entomology 33A:325- 326 . 1945) 17. Roberts , A. N. and C. A. Boll er. Holly production 1n Oregon . Corvallis , Oregon state college, 1953. 32p. (Oregon . Agricultura l ex periment station. Station bulletin no . 1+55) 18. ~andere , J . G. The identity and synonymy of some of our ~ oft s cale insect s . Journal of economic entomology 2;428- 448 . 1909. 19. Schuh, Joe and Don c. Mote. Insect pests of nursery and ornamental trees and shrubs in Oregon. Corvallis , Oregon state college, 1948. 164p. (Oregon. Agricultura l ex periment s t a tion . St a tion bulletin no . 449) 20 . Ste1nweden , John Benjamin. Bases for the generic classifica tion of the Coc coid family Coccidae . Annal s of t he entomologica l society of America 22(2):197- 205. 1929. 45 21 . Steinweden, John Benjamin. Characteristics of some of our Californi soft scale insects , (Coccidae), Monthly bulletin of the California state department of agriculture 19(8):561- 571 . 1930 . 22 . Thompson, w. R. A catalogue of the parasites and predators of insect pests . Sect. 1. Pt . 3 . Belleville, Ontario, Imperial parasite service, 1944. 149p . 23 . Thro, William c. Distinctive characteristics of the s ec1es of the genus Lecan1um . Ithaca, Cornell university, 1903 . 20p . (New York . Agricultural experinent station. Bulletin no . 209) 24. u. s. Department of commerce. Weather bureau. Climatological data 59(10):144- 145 . October 1953 . 25. • 59 (11): 158-170. No~ember 1953 . 26 . • 60(6) :82- 100 . June 1954 . 27. • 60(7):102- 113 . July 1954 . 28 . • 60(8):116- 128 . August 1954 . 29. • 60(9):132- 144 . ~ eptember 1954 . 30 . \'lille , J . E. Estado sanitario vegetal de Oanchaque y Chulucanus . (The condition of cultivated plants in the di stricts of Canchaque and Chulucanus) Boletin direocion agricultura ganaderia 36- 43: 158-164. 1942 . (Ab stracted in Rev1e~ of npplied entomology 31A:120 . 1943) 31 . Woglum, R. D. et al . The effect of f1e1d- ap lied insecticides on beneficial insects of c1trus 1n California . Journal of economic entomo logy 40:818- 820 . 1947. APPENDIX 46 Figure 1. Soft brown scale. A fully matured adult and two crawlers. Living specimens on holly. Eleven times natural size. ----~ ----